1. Field of the Invention
The present invention relates to a liquid crystal display panel for displaying an optical image by modulating an incident light, a display system for magnifying and projecting an image formed on the liquid crystal display panel, and a display system for displaying a reproduced image of a video camera or the like.
2. Description of the Prior Art
A display device employing a liquid crystal display panel has been studied and developed widely because of its compact size and its light weight. Recently, pocket television sets employing a twisted nematic (TN) mode liquid crystal display panel have been used practically. Furthermore, image projection type television systems, viewfinders, and the like using the liquid crystal display panel have also been used practically.
A TN mode liquid crystal display panel has disadvantages such as low display brightness and a short use time of a battery power source due to high dissipation power needed for the light source and due to the necessity of the two polarization plates.
A liquid display panel using a polymer liquid crystal instead of a twisted nematic liquid crystal and an image projection type television system using the liquid crystal panel are disclosed in Japanese Laid Open Patent Publication No. 98,022/1991. The prior art uses a liquid crystal in which the anisotropy .DELTA.n of the refractive index is 0.18 or more. However, such a liquid crystal has poor stability with respect to heat and light and a poor voltage retention rate. Thus, it cannot be used practically. The average diameter of the droplets of liquid crystal is stated to be controlled by the wavelength of the main component such as green of the incident light. However, it is not disclosed that the diameter is changed for each pixel, and a good contrast cannot be attained for an incident light of wide wavelength band.
U.S. Pat. No. 4,613,207 discloses that a polymer dispersed liquid crystal panel is used for a projection type television system. However, a high contrast cannot be realized similarly to the above-mentioned prior art, and uses as a viewfinder and the like are not disclosed.